KMT-2021-BLG-0171Lb and KMT-2021-BLG-1689Lb: two microlensing planets in the KMTNet high-cadence fields with followup observations

• DOI: 10.1093/mnras/stac2023
• Publication Date: 2022-07-21T19:49:08Z
• Authors: Hongjing Yang; Weicheng Zang; Andrew Gould; Jennifer C Yee; Kyu-Ha Hwang; Grant Christie; Takahiro Sumi; Jiyuan Zhang; Shude Mao; ; Michael D Albrow; Sun-Ju Chung; Cheongho Han; Youn Kil Jung; Yoon-Hyun Ryu; In-Gu Shin; Yossi Shvartzvald; Sang-Mok Cha; Dong-Jin Kim; Hyoun-Woo Kim; Seung-Lee Kim; Chung-Uk Lee; Dong-Joo Lee; Yongseok Lee; Byeong-Gon Park; Richard W Pogge; ; John Drummond; Dan Maoz; Jennie McCormick; Tim Natusch; Matthew T Penny; Wei Zhu; ; Ian A Bond; Fumio Abe; Richard Barry; David P Bennett; Aparna Bhattacharya; Martin Donachie; Hirosane Fujii; Akihiko Fukui; Yuki Hirao; Yoshitaka Itow; Rintaro Kirikawa; Iona Kondo; Naoki Koshimoto; Man Cheung Alex Li; Yutaka Matsubara; Yasushi Muraki; Shota Miyazaki; Greg Olmschenk; Clément Ranc; Nicholas J Ratten...; Yuki Satoh; Hikaru Shoji; Stela Ishitani Silva; Daisuke Suzuki; Yuzuru Tanaka; Paul J Tristram; Tsubasa Yamawaki; Atsunori Yonehara
• Keywords: Gravitational microlensing; Degeneracy (biology); Spitzer Space Telescope; Astrometry

Follow-up observations of high-magnification gravitational microlensing events can fully exploit their intrinsic sensitivity to detect extrasolar planets, especially those with small mass ratios. To make followup more uniform and efficient, we develop a system, HighMagFinder, based on the real-time data from Korean Microlensing Telescope Network (KMTNet) automatically alert possible ongoing events. We started new phase follow-up help HighMagFinder in 2021. Here report discovery two planets events, KMT-2021-BLG-0171 KMT-2021-BLG-1689, which were identified by HighMagFinder. find that both suffer ``central-resonant'' caustic degeneracy. The planet-host mass-ratio is $q\sim4.7\times10^{-5}$ or $q\sim 2.2\times10^{-5}$ for KMT-2021-BLG-0171, $q\sim2.5\times10^{-4}$ 1.8\times10^{-4}$ KMT-2021-BLG-1689. Together reported Ryu et al. (2022), four cases such degeneracy have been discovered 2021 season alone, indicating degenerate solutions may missed some previous studies. also propose factor weighting probability each solution phase-space. resonant interpretations are disfavored under this consideration. This be included future statistical studies weight solutions.